C# 即使使用默认设置,Json.NET也会将枚举序列化为字符串
我使用的是Json.NET7.0.1 报告说C# 即使使用默认设置,Json.NET也会将枚举序列化为字符串,c#,json,json.net,C#,Json,Json.net,我使用的是Json.NET7.0.1 报告说 Enum[序列化为]整数(可以是StringEnumConverter的枚举值名称) 在my Global.asax.cs中,我指定默认设置如下: JsonConvert.DefaultSettings = (() => { var settings = new JsonSerializerSettings(); settings.Converters.Add(new StringEnumConverter()); re
Enum
[序列化为]整数(可以是StringEnumConverter的枚举值名称)
在my Global.asax.cs中,我指定默认设置如下:
JsonConvert.DefaultSettings = (() =>
{
var settings = new JsonSerializerSettings();
settings.Converters.Add(new StringEnumConverter());
return settings;
});
但是,在某些情况下,我希望enum
被序列化为整数,例如,当我构建一个要存储在数据库中的JSON时
我是这样做的:
public class JsonSerializedType<T> : IUserType where T : class
{
private static readonly JsonSerializerSettings serializerSettings = new JsonSerializerSettings();
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
cmd.Parameters[index].Value = JsonConvert.SerializeObject(value as T, serializerSettings);
}
}
公共类JsonSerializedType:IUserType其中T:class
{
私有静态只读JsonSerializerSettings serializerSettings=新JsonSerializerSettings();
public void NullSafeSet(IDbCommand cmd,对象值,int索引)
{
cmd.Parameters[index].Value=JsonConvert.SerializeObject(值为T,serializerSettings);
}
}
但是,即使在这种情况下,枚举
也被序列化为字符串。我检查了serializerSettings
是否没有converter
,其ContractResolver
是否为null
为什么会这样?原因
我们在这里看到的行为是经过设计的,JsonConvert
方法中传递的设置与提供的DefaultSettings
合并,下面是JsonSerializer类中Json.Net源代码的一小部分,以澄清这种情况
private static void ApplySerializerSettings(JsonSerializer serializer, JsonSerializerSettings settings)
{
if (!CollectionUtils.IsNullOrEmpty(settings.Converters))
{
// insert settings converters at the beginning so they take precedence
// if user wants to remove one of the default converters they will have to do it manually
for (int i = 0; i < settings.Converters.Count; i++)
{
serializer.Converters.Insert(i, settings.Converters[i]);
}
}
其用法如下所示:
var json = JsonConvert.SerializeObject(obj,
new JsonSerializerSettings
{
Converters = new List<JsonConverter> {new PreventStringEnumConverter()}
});
var json=JsonConvert.SerializeObject(obj,
新JsonSerializerSettings
{
转换器=新列表{new PreventStringEnumConverter()}
});
之所以发生这种情况,是因为通过内部调用将传入设置应用于默认设置之上。我不知道是否/在何处记录了此行为,但它在中可见。因此,除了本地指定转换器的空列表外,还将使用默认的转换器列表,这意味着将使用默认的StringEnumConverter
您有几个选项可以解决此问题:
public static class JsonExtensions
{
public static string SerializeObjectNoDefaultSettings(object value, Formatting formatting, JsonSerializerSettings settings)
{
var jsonSerializer = JsonSerializer.Create(settings);
jsonSerializer.Formatting = formatting;
StringBuilder sb = new StringBuilder(256);
StringWriter sw = new StringWriter(sb, CultureInfo.InvariantCulture);
using (JsonTextWriter jsonWriter = new JsonTextWriter(sw))
{
jsonWriter.Formatting = jsonSerializer.Formatting;
jsonSerializer.Serialize(jsonWriter, value);
}
return sw.ToString();
}
}
然后像这样使用它:
var json = JsonExtensions.SerializeObjectNoDefaultSettings(value, Formatting.None, new JsonSerializerSettings());
var json = JsonConvert.SerializeObject(value, Formatting.None, new JsonSerializerSettings { Converters = new JsonConverter[] { new IntegerEnumConverter() } });
StringEnumConverter
替换为不将枚举序列化为字符串的转换器,例如:
public class IntegerEnumConverter : StringEnumConverter
{
public override bool CanRead { get { return false; } }
public override bool CanWrite { get { return false; } }
}
然后像这样使用它:
var json = JsonExtensions.SerializeObjectNoDefaultSettings(value, Formatting.None, new JsonSerializerSettings());
var json = JsonConvert.SerializeObject(value, Formatting.None, new JsonSerializerSettings { Converters = new JsonConverter[] { new IntegerEnumConverter() } });
本地指定的转换器将优先于默认转换器